Well.. i tested the GPS out while driving along KL-Putrajaya Highway heading towards airport. As I'm not on unlimited 3G data plan.. ouch!

Well.. it works most of the time (I can't really confirm because I'm driving and glancing at it once in a while. But one thing for sure.. I notice the current location DOT moving along and my 3G signal is full. I turn the map to just use only the street signs to ensure minimal data download. One thing about Google Maps implementation as compared to Nokia Maps are the followings:
1) Nokia Maps have voice navigation and the maps are updated
2) Google Maps although quite accurate but some portion of the map is not reflecting current infrastructure ie. KL-Putrajaya Highway (it means I can see a blue dot moving along the map but there's no road and there's no street signs.. like moving through empty air until I reach Cyberjaya exit whereby the Elite highway is reflected)

So, my overall point of view, GPS signal is quicker to lock in my area as compared to my N80 paired with a Bluetooth GPS receiver, but when you input FROM and TO, most of the time, it can't get any directions for you unlike the same thing I tried for Nokia Maps. Tried lots of scenario but somehow, always get the can't retrieve directions error thingy.

Overall, i felt, once there's a 3rd party GPS apps available and it uses updated maps (ie. Mapking or Malsing), GPS will really shine for iPhone 3G. Until then, the GPS is just a novelty.

p/s: Last weekend, I got lost in Shah Alam and thank God the GPS is able to show me where I am and where I want to go (manually).